Large machines such as, for example, wheel loaders, off-highway haul trucks, excavators, motor graders, and other types of earth-moving machines are used to perform a variety of tasks. Some of these tasks involve intermittently moving between and stopping at certain locations within a worksite and, because of the poor visibility provided to operators of the machines, these tasks can be difficult to complete safely and effectively. In fact, it is not uncommon for obstacles, such as light duty vehicles, to move and stop near the machine completely unnoticed by the operator. When an obstacle remains unnoticed, the machine may move toward and collide with the obstacle. This collision may necessitate an accident investigation. During this accident investigation, the machine may be taken out of service, thereby reducing the productivity and efficiency of the worksite.
One way to minimize the effect of obstacles near a machine is described in U.S. Pat. No. 6,487,500 (the '500 patent) issued to Lemelson et al. on Nov. 26, 2002. The '500 patent describes a vehicle equipped with a collision avoidance warning and control system. The collision avoidance warning and control system includes GPS location and computing systems supplemented by additional sensors including video scanners, radars/lidars, speedometers, and/or accelerometers. Together with the GPS location and computing systems, these sensors output vehicle location information and information concerning objects that represent impending collision situations for the vehicle. Onboard vehicle fuzzy logic/expert system computing algorithms use these outputs to derive warning and control signals. Based on the warning signals, a video display highlights hazards on real time camera images and displays special warning images such as flashing lights, alpha-numeric messages, distance values, and speed indicators. Based on the control signals, a brake system, acceleration system, steering system, communications system, horn, light, windshield wiper, seat, mirror, air conditioner, heater, and/or defogger is operated to avoid or minimize the effect of a collision.
Although the collision avoidance warning and control system of the '500 patent may detect objects that represent impending collision situations for a vehicle, it may do little to detect obstacles that are relatively motionless with respect to the vehicle. Furthermore, though the collision avoidance warning and control system of the '500 patent may warn an operator of an impending collision situation, it may do little to ensure a vehicle operator recognizes and/or acknowledges the situation. In addition, though the expert system computing algorithms of the '500 patent may derive control signals designed to avoid or minimize the effect of vehicle collisions, the expert system computing algorithms may be unnecessary and prohibitively expensive for certain applications. In particular, the expert system computing algorithms of the '500 patent may necessitate more powerful computing hardware, thereby substantially increasing the system's cost while providing what may be a marginal benefit.
The disclosed system is directed to overcoming one or more of the problems set forth above.